The green from “The Grinch” amounted to the fifth-highest gross ever for a pic’s third weekend, topped only by “Twister,” “Titanic,” “Star Wars: Episode 1 — The Phantom Menace” and “Jurassic Park.” Even though the phenom fell 48% from the previous outing, the decline was milder than U expected and portends continued boffo biz through the holidays.

“We are looking at a $300 million trajectory,” noted Tom Borys, prexy of B.O. tracker ACNielsen EDI. “The ‘Grinch’ numbers this weekend really speak to the momentum of this film.”

U’s distrib chief Nikki Rocco said “The Grinch” had topped internal forecasts, noting that family fare typically declines by as much as 55% during the Friday-Sunday after the Thanksgiving break. “What’s left to say is that we have a mega-hit that’s satisfying holiday audiences,” she added.

Rocco also pointed out that “Grinch” will soon eclipse the $181.4 million domestic gross for Imagine’s current record holder, “Liar Liar.”

‘Unbreakable’ still strong

Disney’s “Unbreakable” also remained solid with $15 million in its soph session to hit $66.7 million in a dozen days. Mouse House distrib chief Chuck Viane said the thriller’s 50% drop matched internal predictions and also heralded continued playability for the entire slate in coming weeks.

“We’re definitely back on track for the rest of the year,” he added. “This weekend looks very good for the long-term health of the business.”

“Grinch” may rack up a fourth No. 1 trophy in the weekend ahead, although Warner Bros. reported “excellent” response and 85% capacity at 503 Saturday night sneaks of action-thriller “Proof of Life,” which will break Friday at about 2,700 playdates. Also opening wide will be New Line’s fantasy-actioner “Dungeons and Dragons” and Sony’s mountain-climbing drama “Vertical Limit.”

Borys believes upcoming fare plus the continued one-two punch of “Grinch” and “Unbreakable” should maintain solid B.O. performance for the rest of the year. “We have a great foundation in the business at this moment,” he added.

With the top two pics accounting for 45% of all sales, overall B.O. hit more than $92 million, up 14% from the same weekend last year when the second weekend of “Toy Story 2″ led with $27.8 million. Year-to-date cume hit $6.7 billion, edging ahead of last year’s figure by about $20 million.

B.O. flip-flop

For the third time in four years, studios took a break from new wide releases, giving the order of the weekend’s Top 10 list a familiar feel. The only change saw last weekend’s No. 8 finisher, Fox’s “Men of Honor,” swapping the seventh spot with Sony’s “The 6th Day.”

“Honor” posted the Top 10’s smallest weekend-to-weekend decline at 39%, followed by the 42% for “Meet the Parents” and 44% for “Bounce” as business skewed toward more mature audiences. U’s “Parents,” which kept the fall B.O. from tanking, has raised $153.2 million in 59 days.

With families no longer mobbing multiplexes, the third weekend of “Rugrats in Paris” posted the biggest decline among the Top 10 at 63%, followed by 59% for “102 Dalmatians.” The sequels have totaled $55.6 million and $36.5 million, respectively.

U, which will roll out “The Family Man” on Dec. 22, led in market share with 37% for the weekend. Disney, which has “The Emperor’s New Groove” set for Dec. 15, followed with 29%.